Suggestions on fixing controllers??

[Kai]

Over time, I have come to amass a huge collection of spare controllers; for the PS1, 6 of them, which only half work (2 of the earliest controllers and 1 with the control sticks); a 3rd-Party N64 controller; and my poor Logitech Dual-Action with it's sticky, barely-functional D-Pad (I got it well used).

I already have a pretty good grasp on how to fix the PS1 controllers, and spare parts; I even have an empty plastic shell I can use to make a whole new controller, if I really wanted to try...

But i'm wondering about the other two. In particular, for the N64 controller, it just doesn't function so well. If I stripped it for parts, I wonder if I could theoretically replace the control stick on one of my actual controllers with this one, since the joystick in this one seems to be built fairly well in comparison.
This is roughly the same as the one i'm referring to.

And for my poor PC controller... I just tried stretching the spring in the underside of the D-Pad. Good news is, now the D-pad works (it didn't before); bad news, it sticks a lot and it's incredibly stiff. I'm wondering if I should just hock it for a new one, or if I could still save it??

[Kai]

I believe it is a module... but i'm definitely going to give it a shot. Thanks for the tip! :3